fissile

"Iran has been at a near-zero breakout for months," she told the BBC, referring to the time it would take Iran to acquire enough fissile material for one bomb if it chose to do so.

It is unclear when Mr Kim made the visit and if the site is at the North's sprawling Yongbyon nuclear complex, which produces fissile material for Pyongyang's nuclear weapons.

Washington, however, is preparing to conduct next year at the Nevada Test Site two so-called subcritical experiments involving fissile materials in amounts too small to ignite a nuclear explosion.

President Joe Biden’s failure to revive it, Iran could make the fissile material for one bomb in 12 days or so, according to U.S. estimates, down from a year when the accord was in force.

“I don’t think they are short of fissile materials,” said Mr. Lankov.